/**
 * Copyright 2010-present Facebook.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.facebook;

/**
 * <p>
 * Identifies the state of a Session.
 * </p>
 * <p>
 * Session objects implement a state machine that controls their lifecycle. This
 * enum represents the states of the state machine.
 * </p>
 */
public enum SessionState
{
  /**
   * Indicates that the Session has not yet been opened and has no cached
   * token. Opening a Session in this state will involve user interaction.
   */
  CREATED(Category.CREATED_CATEGORY),

  /**
   * <p>
   * Indicates that the Session has not yet been opened and has a cached
   * token. Opening a Session in this state will not involve user interaction.
   * </p>
   * <p>
   * If you are using Session from an Android Service, you must provide a
   * TokenCachingStrategy implementation that contains a valid token to the Session
   * constructor. The resulting Session will be created in this state, and you
   * can then safely call open, passing null for the Activity.
   * </p>
   */
  CREATED_TOKEN_LOADED(Category.CREATED_CATEGORY),

  /**
   * Indicates that the Session is in the process of opening.
   */
  OPENING(Category.CREATED_CATEGORY),

  /**
   * Indicates that the Session is opened. In this state, the Session may be
   * used with a {@link Request}.
   */
  OPENED(Category.OPENED_CATEGORY),

  /**
   * <p>
   * Indicates that the Session is opened and that the token has changed. In
   * this state, the Session may be used with {@link Request}.
   * </p>
   * <p>
   * Every time the token is updated, {@link Session.StatusCallback
   * StatusCallback} is called with this value.
   * </p>
   */
  OPENED_TOKEN_UPDATED(Category.OPENED_CATEGORY),

  /**
   * Indicates that the Session is closed, and that it was not closed
   * normally. Typically this means that the open call failed, and the
   * Exception parameter to {@link Session.StatusCallback StatusCallback} will
   * be non-null.
   */
  CLOSED_LOGIN_FAILED(Category.CLOSED_CATEGORY),

  /**
   * Indicates that the Session was closed normally.
   */
  CLOSED(Category.CLOSED_CATEGORY);

  private final Category category;

  SessionState(Category category)
  {
    this.category = category;
  }

  /**
   * Returns a boolean indicating whether the state represents a successfully
   * opened state in which the Session can be used with a {@link Request}.
   *
   * @return a boolean indicating whether the state represents a successfully
   * opened state in which the Session can be used with a
   * {@link Request}.
   */
  public boolean isOpened()
  {
    return this.category == Category.OPENED_CATEGORY;
  }

  /**
   * Returns a boolean indicating whether the state represents a closed
   * Session that can no longer be used with a {@link Request}.
   *
   * @return a boolean indicating whether the state represents a closed
   * Session that can no longer be used with a {@link Request}.
   */
  public boolean isClosed()
  {
    return this.category == Category.CLOSED_CATEGORY;
  }

  private enum Category
  {
    CREATED_CATEGORY, OPENED_CATEGORY, CLOSED_CATEGORY
  }
}
